Process for making a spunmelt nonwoven batt or web from recycled polypropylene

Abstract

A process for making a spunmelt nonwoven web including the steps of providing a mixture of recycled polypropylene, extruding the recycled polypropylene mixture to form a molten recycled polypropylene mixture, filtering the molten recycled polypropylene mixture through a filter to form recycled polypropylene filtrate, dosing the recycled polypropylene filtrate into the spunmelt production line by an amount of 80% to 100% by weight, passing the recycled polypropylene filtrate through at least one spinneret of the spunmelt production line to form filaments at a spinning speed of greater than 1200 meters per minute, cooling and drawing the filaments, and depositing the filaments on a moving belt to form at least one layer of the spunmelt nonwoven web made up of 80% by 100% by weight of recycled polypropylene fibers.

The invention claimed is: 
     
       1. A process for making a spunmelt nonwoven web on a spunmelt production line, comprising:
 providing a mixture of recycled polypropylene; 
 extruding the recycled polypropylene mixture to form a molten recycled polypropylene mixture; 
 filtering the molten recycled polypropylene mixture through a filter to form recycled polypropylene filtrate having a melt flow rate within a range of 20 g/10 min to 100 g/10 min as tested in accordance with ASTM 1238, the filter having a mesh size that is finer than a mesh size of a finest filter used in the spunmelt production line by a factor of at least 1.1; 
 dosing the recycled polypropylene filtrate into the spunmelt production line by an amount of 100% by weight; 
 passing the recycled polypropylene filtrate through at least one spinneret of the spunmelt production line to form filaments at a spinning speed of greater than 1200 meters per minute, the formed filaments being mono-component, bicomponent or multicomponent filaments, all polypropylene components of the filaments comprising 100% by weight recycled polypropylene; 
 cooling and drawing the filaments; and 
 depositing the filaments on a moving belt to form at least one layer of the spunmelt nonwoven web made up of 100% by weight of recycled polypropylene fibers. 
 
     
     
       2. The process of  claim 1 , wherein the melt flow rate of the recycled polypropylene filtrate is within a range of 25 g/10 min to 55 g/10 min as tested in accordance with ASTM 1238. 
     
     
       3. The process of  claim 2 , wherein the recycled polypropylene filtrate comprises stabilizers, antioxidants, or nucleating agents up to 2% by weight. 
     
     
       4. The process of  claim 1 , wherein the filament spinning speed is within a range of 2000-3500 meters per minute. 
     
     
       5. The process of  claim 1 , wherein the step of depositing comprises depositing the filaments on a moving belt to form a plurality of layers of the spunmelt nonwoven web, with the at least one layer of the plurality of layers made up of 100% by weight of recycled polypropylene. 
     
     
       6. The process of  claim 1 , wherein the recycled polypropylene fibers have a linear mass density within the range of 0.8 to 3.0 denier. 
     
     
       7. The process of  claim 5 , wherein the recycled polypropylene fibers have a linear mass density within the range of 1.4 to 1.9 denier. 
     
     
       8. The process of  claim 1 , wherein the spunmelt nonwoven web has a basis weight within the range of 8 gsm to 90 gsm. 
     
     
       9. The process of  claim 1 , wherein the spunmelt nonwoven web has a basis weight within the range of 10 gsm to 40 gsm. 
     
     
       10. The process of  claim 1 , wherein the spunmelt nonwoven web has a machine direction tensile strength that is decreased not more than 20% as compared to a machine direction tensile strength of a spunmelt nonwoven web made with virgin polypropylene under the same process conditions. 
     
     
       11. The process of  claim 1 , wherein the spunmelt nonwoven web has a cross direction tensile strength that is decreased not more than 20% as compared to a cross direction tensile strength of a spunmelt nonwoven web made with virgin polypropylene under the same process conditions. 
     
     
       12. The process of  claim 1 , wherein the spunmelt nonwoven web has a machine direction tensile strength that is decreased not more than 15% as compared to a machine direction tensile strength of a spunmelt nonwoven web made with virgin polypropylene under the same process conditions. 
     
     
       13. The process of  claim 1 , wherein the spunmelt nonwoven web has a cross direction tensile strength that is decreased not more than 15% as compared to a cross direction tensile strength of a spunmelt nonwoven web made with virgin polypropylene under the same process conditions. 
     
     
       14. A process for making a spunmelt nonwoven batt on a spunmelt production line, comprising:
 providing a mixture of recycled polypropylene; 
 melting the recycled polypropylene mixture to a polymer melt via extrusion; 
 filtering the polymer melt through a filter to form recycled polypropylene filtrate; 
 forming recycled polypropylene by solidifying the recycled polypropylene filtrate having a melt flow rate within a range of 30 g/10 min to 100 g/10 min as tested in accordance with ASTM 1238; 
 dosing the recycled polypropylene into the spunmelt production line by an amount of 100% by weight and melting the dosed recycled polypropylene; 
 passing the dosed recycled polypropylene through at least one filter within the spunmelt production line, a ratio of the mesh of the filter used in the step of filtering the polymer melt to the mesh of a finest filter of the at least the one filter used in the spunmelt production line being at least 1.1; 
 passing the recycled polypropylene through a spinneret of the spunmelt production line to form filaments at a spinning speed of greater than 1200 meters per minute, the formed filaments being monocomponent, bicomponent or multicomponent filaments, all polypropylene components of the filaments comprising 100% by weight recycled polypropylene; 
 cooling and drawing the filaments; and 
 depositing the filaments on a moving belt to form a nonwoven batt made up of fibers comprising 100% by weight recycled polypropylene. 
 
     
     
       15. The process of  claim 14 , wherein the nonwoven batt is bonded to form a nonwoven web. 
     
     
       16. The process of  claim 14 , wherein during or after the step of depositing the filaments on a moving belt the nonwoven batt is laid onto at least one further layer of fibers and/or at least one further layer of fibers is formed and laid onto the nonwoven batt to form a multilayer nonwoven web. 
     
     
       17. The process of  claim 14 , wherein the melt flow rate of the recycled polypropylene is within a range of 35 g/10 min to 55 g/10 min as tested in accordance with ASTM 1238. 
     
     
       18. The process of  claim 14 , wherein the filament spinning speed is within a range of 2000-3500 meters per minute. 
     
     
       19. The process of  claim 14 , wherein the recycled polypropylene fibers have a linear mass density within the range of 0.8 to 3.0 denier. 
     
     
       20. The process of  claim 17 , wherein the recycled polypropylene fibers have a linear mass density within the range of 1.4 to 1.9 denier. 
     
     
       21. The process of  claim 14 , wherein the spunmelt nonwoven has a basis weight within the range of 8 gsm to 90 gsm. 
     
     
       22. The process of  claim 14 , wherein the spunmelt nonwoven has a basis weight within the range of 10 gsm to 40 gsm.